Emergency rooms in communities with indoor smoking bans reported a 17 percent decrease in the number of children needing care for asthma attacks, according to new research from the University of Chicago Medicine. The study, led by pediatric allergy expert Christina Ciaccio, MD, assistant professor of pediatrics at the University of Chicago, examined 20 metropolitan areas around the country that introduced clean indoor air regulations prohibiting smoking in public places such as restaurants, hotels and workplaces. The study, co-authored by researchers from Brown University and Kansas University, was published in the Annals of Allergy, Asthma & Immunology.

"Children are in a very unique situation in that they have very little control over their environment," Ciaccio said, adding that changing public policies is one way to help control the environment for children in public spaces. "This study shows that even those short exposures to secondhand smoke in public spaces like restaurants can have a significant impact on asthma exacerbations."

The researchers reviewed asthma-related emergency department visits that occurred between July 2000 and January 2014. The data came from 20 hospitals in 14 different states and the District of Columbia. For each hospital, the researchers counted the number of visits during the three years before and the three years after indoor smoking bans took effect.

"Combined with other studies, our results make it clear that clean indoor air legislation improves public health," said study co-author Theresa Shireman, PhD, professor in the Brown University School of Public Health.

All told, the team reviewed data from 335,588 emergency room visits. When making pre-ban and post-ban comparisons, they controlled for a variety of possible factors including seasonality and things like patient gender, age, race and socioeconomic status.

Results varied by community, but declined in the majority of locales. In the aggregate across all 20 hospitals, the reduction in ER visits became deeper with every passing year following the bans. Children's ER visits fell 8 percent after one year, 13 percent after two years and, finally, 17 percent after three years.

The researchers also found there was no general, nationwide decline in children's asthma-related emergency room visits beyond those seen in communities with the smoking bans. The researchers acknowledged the study only shows an association and doesn't prove the bans caused the drop in emergency room visits, but Shireman said the evidence strongly suggests it.

"We should all breathe easier when our children do," said Tami Gurley-Calvez, PhD, associate professor of health policy and management at Kansas University and the paper's third author.

The paper was titled "Indoor tobacco legislation is associated with fewer emergency department visits for asthma exacerbation in children."